Process for stabilizing biologically active materials with modified collagen hydrolyzate



3,322,632 raocnss sou sTABrLiZiNG nioLoGicALLY AC- The present invention relates to a process for stabilizing biologically active materials such as bacteria, bacterial metabolites, viruses, sera and enzymes.

Many biologically active materials lose their potency partially or completely, w-hen dissolved, freeze-dried or stored. Therefore, attempts have been made to improve the stability and storability of such materials by adding a stabilizer. However, no stabilizer which could be generally used for the stabilization of bacteria, bacterial metabolites, viruses, sera and enzymes, and which could remain in the solution of the biologically active substance even if this solution were used intravenously, has heretofore been known.

For vaccines to be valuable products, they must be standard preparations having a potency that remains constant over a prolonged period of time. The stability of the biologically active substances must also be maintained during the preparation of the vaccines. Thus, for example, in order to stabilize polio-virus containing suspensions during the production of polio vaccines, the poliovirus suspensions have heretofore been frozen and then stored in deep-freeze chambers. This method of stabilizing between the various steps of preparation is very expensive. Stability furthermore plays an important role for antibody-containing sera and enzymes, especially those used in the form of solutions in permanent drop infusions at about 20 C. Streptokinase, a metabolite of several streptococci strains, which is able to dissolve fibrin thromboses by converting plasminogen into plasmin and which is therefore of utmost importance in the therapy of venous and arterial thromboscs, thrombophlebitides and pulmonary emboli, loses its potency during storage, even when stored in dry state, at a temperature of 4 C., especially at higher temperatures, for example, those to which it is exposed during transportation into the tropics. Hitherto, such shipments have always involved a loss of activity in the material.

Now, we have found a process for stabilizing biologically active materials such as bacteria, bacterial metabolites, viruses, pera, and enzymes, wherein 05-50 percent of a material containing urea-alkylene-urea groups and obtained by the process described in German Patent 1,118,792 by hydrolytic degradation of collagen, preferably gelatin, to a molecular weight of 2000 to 20,000, preferably 5000 to 10,000, and then cross-linking with a diisocyanate to have a molecular weight of about 15,000 to 60,000, or obtained according to the process described in US. Patent 3,057,782 by cross-linking collagen, preferably gelatin, with a diisocyanate followed by hydrolytic degradation to a molecular weight of, for example, 15,000 to 60,000, preferably in combination with 05-50% of sodium-L-glutaminate, is added to the said biologically active materials.

The collagen degradation product cross-linked with diisocyanate has the advantage that it has no antigenic properties.

The following examples which are intended for the purpose of illustration of the process of the invention and not for limitation, show that the biologically active mate- 'rials stabilized according to the invention retain their 3,322,032 Patented May 30, 1967 biological activity in solution, in freeze-dried state or during storage.

The examples refer to the stabilization of bacterial preparations [Pertussis, Bacillus Calmette Gurin (BCG)], metabolites of bacteria (diphtheria and tetanus toxoid, tuberculin), viruses (poli-oviruses of all three types), sera (ri-ckcttsiosis antiserum) and enzymes (plasmin, streptokinase). As is also shown in the examples (cf. diphtheria and tetanus toxoid), the substances used as vaccine may contain in known manner an adjuvant, for example, aluminium hydroxide, for increasing the antigenicity.

Example I.-Pertussis germs 500 cc. of a 3.5% solution of the gelatin degradation product obtained according to Example 1 of German Patent 1,118,792 and cross-linked with hexamethylenediisocyanate, were added to 500 cc. of a suspension of pertussis germs having a titer of 30x10 germs per cc. and showing in the mouse protection test (Kendrick test) an average of 20 units of protection per cc. (hereinafter referred to as UP), and the whole was then freezedried.

A corresponding suspension of pertussis germs was freeze-dried for the purpose of comparison.

In mouse protection tests carried out with the freezedried products, which had been dissolved in equal volumes of distilled water for the tests, it was found that the preparation without the product of degraded gelatin crosslinked with diisocyanate, had an average of 4.5 UP, whereas the preparation with the additive had an average of 18 UP.

Example 2.Bacillus Calmette Guerz'n (ECG) (with combined stabilizer) (A) 0.5% of the stabilizer used in Example 1 and 2% of sodium-L-glutan'iinate were added to 300 cc. of a BCG- containing suspension containing per cc. 5 mg. of BCG germs, the suspension was then filled in ampules, freezedried and closed by melting under reduced pressure. The number of live germs per milligram of dry substance was 17.0 X 10 The ampules prepared in the above manner were stored at 37 C. After 2 months, the number of germs capable of reproduction was determined. It was found to be after this time 2.7 10 per mg, thus 15% of the quantity used initially.

The BCG vaccine thus obtained was readily soluble, easy to handle and had after a storage period of 2 months at 37 C. a titer of BCG germs capable of reproduction suflicient for protective vaccination.

(B) A BCG dry vaccine prepared in known manner for the purpose of comparison, containing 15% of lactose and 1.5% of sodium-L-glutaminate, had after storage for 2 months at 37 C. a titer of 0.2 10 BCG germs capable of reproduction per mg. of dry vaccine. Hence, the additives used did not sufiicient.y stabilize the BCG vaccine, so that after 2 months it was no longer suitable for protective vaccination.

(C) Drying of the BCG-ger-ms without any additive is not possible, because they cannot be suspended thereafter.

Example 3.-Diphtheria and tetanus toxoid cc. of a solution of 3.5% strength of a gelatin degradation product cross-linked with =hexamet-hylene-diisocyanate were added to 100 cc. of a diphtheria-tetanus combination vaccine containing 0.2% of AI(OH as in Example 1. A further 100 cc. of the same vaccine were diluted with 100 cc. of a sodium chloride solution of 0.85% strength. The solutions were then freeze-dried and after solution of the freeze-dried products the units of protection against diphtheria and tetanus were determined.

The. data obtained are compared in the following table, the values in brackets showing the range of dispersion:

UP against UP against diphtheria tetanus With gelatin degradation product cross-linked with diisocyanate 120(100-150) 120 (100-150) With NaCl 58(44-75) 26(20-34) It is evident from the above table that the NaCl values are remarkably reduced, whereas the values obtained using the stabilizer of the present invention prove the good action of'this stabilizer on diphtheria and tetanus toxoid.

Example 4.Polimyelitis virus type I/Mahoney at 20 C.

2.6% of a physiological (0.85 sodium chloride solution of the stabilizer used in Example 1 were added to 100 cc. of a suspension of poliovirus type I/Mahoney, having a titer of 10"- ID /cc., the whole was then stored for 9 weeks at 20 C. and then the titer was again determined. It was found to be l0 ID /cc.

Another solution without stabilizer stored for comparison at 20 C. exhibited after 8 weeks a titer of ID5o/CC- Example 5.-P0li0myelz'tis virus type l/Mahoney at 37 C.

A poliovirus suspension like that described in Example 4 was stored for 21 days at 37 C. After this time, the suspension containing the stabilizer had a titer of 10 whereas the titer of the control suspension had already on the 13th day fallen to an unmeasurable value.

Example 6.P0li0myelitis virus type I/Mahoney at 4 C.

When the p'oliovirus suspension of the foregoing example was stored at 4 C., the following values were obtained:

Poliovirus with stabilizer after 84 weeks 10 ID /cc. POllOVlI'IlS without stabilizer after 84 weeks 10 ID /cc.

Example 7 .-P0li0myelitis virus type III/Leon 12 a g'(Sabin) at C.

2.6% 'of the stabilizer of Example 1 (1.3 g.) were added to 50 cc. of a Sabin poliovirus type III/Leon a b suspension and the whole was stored for 8 weeks at 20 C. After this time, the determination of the titer gave the following results:

Sabin poliovirus with 2.6% of stabilizer After 8 weeks 10 ID cc. Sabin poliovirus without stabilizer 10 ID cc.

After 8 weeks 10 ID cc.

Example 8.-P0li0myelitis vaccine for types I, II and III at 37 C.

100 cc. of an inactivated poliomyelitis vaccine containing all 3 types bf poliovirus were stored for 14 days at 37 C. and then the antigenic activity (serum ID was determined by tests with guinea pigs. 2.6 g. of the stabilizer used in Example 1 were added to another 100 cc. of this polio vaccine and then treated in the same manner. The following values were obtained:

Type I Type II Type III Polio vaccine 16, 320 49, 152 4, 480

Folio vaccine with 2.6% of stabilizer after 14 days 70, 528 16, 480 109, 568 Polio vaccine without stabilizer after 14 days 0 0 0 Example 9.Rickettsia fever antiserum 1,100 cc. of a 1.75% solution of the stabilizer of Example 1, dissolved in a 0.85% sodium chloride solution,

6 were added to 100 cc. of a rickettsia fever antiserum.

After dilution, this solution had a titer of about 1:100.

The solution was then freeze-dried. After re-dissolution in distilled water, a solution was obtained that had a titer of complement binding antibodies of 1:80.

In contradistinction thereto, another rickettsia fever antiserum prepared analogously with a 0.85% sodium chloride solution had a titer of complement binding antibodies of 1:20.

Example 10.-Plasmin (A) A quantity of plasmin contained in 10 cc. of a 0.85% sodium chloride solution, having after solution a titer of 9,600 units per cc. and formed by the action of streptokinase on plasminogen, lost its potency during storage at 20 C. to the extent defined below (one internal plasmin unit being expressed by the quantity of plasmin which dissolves within 15 minutes a standard fibrin thrombus from 1 cc. of a 0.1% bovine fibrinogen solution) Incubation period Plasmin activity in Activity in percent internal units per cc.

The above table shows that after 5 hours the plasmin activity was reduced by about one half.

In contradistinction thereto, the same quantity of plasmin in a 1.75% solution of the stabilizer used in Example 1, showed, when stored at 20 C., only a slight loss of activity, as is evidenced by the table hereunder. The data in this table also prove that the stabilizer added already exerted a stabilizing action during dissolution, since the plasmin activity amounted after dissolution in the 0.85% sodium chloride solution to 9,600 units per cc.

Incubation period Plasmin activity in Activity in percent in hours at 20 0. internal units per cc.

(B) For testing the stability of the plasmin activity of dilute solutions as those used for slow several hours lasting infusions to patients, the quantity of plasmin corresponding to 9,500 internal units was dissolved in cc. of a 0.85% sodium chloride solution and another equal quantity was dissolved in 50 cc. of a 1.75% solution of the stabilizer used in Example 1; the activity was then determined at 20 C. after 2 and 5 hours. The following values were obtained:

The preparation lost a part of its potency already durfreeze-dried and ich was C. for at least one year. Even at C., the preparation retained its several months as is shown by Lu W d e n .1 a b m wa 1 f W O n .m wcm F... m. m wfim f MPM7W .1 am w .wm t m mm me .1 mck se a OeCSH h mbmmm G tl h m o u d io mAnpaJ f m wm a a IT-Mt ing dissolution and when the preparation was allowed to stand at 20 C., the decay of potency was stronger than in the foregoing comparative test carried out with a higher plasmin concentration. After 5 hours, only about 5 one third of the activity could be determined. In contrage when usdespite the high degree With stabilizer, Percent ainirig egg ed hemagthere- Diluted 1:256

l l l l l l l l 1 1 1 1 1 1 1 1 ghest dilution ponds to the and used for the serologi- Activity 1 ercent ptokinase cony even when stored ,500 rev. per minwhich were obyanate and ob r weeks. at 4 C.

With stabilizer Undiluted kTLhllllll Without stabilize compiled in the following penslon stored in diluted state ed state, and, on the other 1:256 with physiological sogenerally introduced in the gelatin degradation product crosspension was diluted with 225 cc.

r, samples of the above-desamples were taken from the gglutination units were detertiter) indicates the hi provokes agglutination of chicken inhibition test which is Castle disease. This dilution, which lution for diagnosis should Diluted 1:256

ution of 1:256 corres g 4 hernagglutination units rnination 0 prolonged period of time, especially Castle disease viruses t, were then taken up in 100 cc. of a sodium chloride solution, and both virus Castle disease virus containing egg liquid,

Without stabilizer Undiluted Streptokinase Filing.-

Example 14.-New-Castle disease virus 100 cc. of New-Castle disease virus cont liquid were centrifuged for 1 hour at 17 ute and the Newtained as sedimen y means of hexamethylenediisoc according to Example 1 of German Patent by the hemagglutination test. The indicat The results of the tests are table, the values of the sus g? 55 having been multiplied by 256.

1 cc. of this virus sus of physiological In corresponding manne scribed Newon the one hand in undilut hand, diluted at a ratio of In intervals of 1 week 4 suspensions and the heme weeks dium chloride solution were stored to mined glutination titer (HA- of virus which still erythrocytes. The dil solution containin the hemagglutination cal method of deter diagnostic of the Newis generally used as s fore, be stable for a for comparative tests.

Storage in l Dissolved After freeze- After 3 weeks at 37 g for After 8 weeks at 37 C... C., samples were taken and the streptokinase activity of these samples was determined. h l1 s vldenc that the stre The following values were obtained; 20 taming stabilizer retained its full activit for 8 weeks at 37 C.

3.5% solution of the 98 linked b tained 57.5

suspensions were stored for 10 weeks at 4 C.

ercent eriod.

batch was prepared as a solution of sodium chloride.

Activity 2 hours after dissolving, percent permanent drop iny of the originally ved after dissolving, 35 ment of the method mpules of 1 cc. capacity, 45 eeze-dried and stored at 37 C. The results of the activity tests are compiled in the following table.

Activity Without stabilizer, Percent ptokinase was sta- 5 6 met Z 10 a Q oh .1 7 fw n m et V 0 6 d h t am new y O I w m% 8 r mg m mm a t. Se at After dissolving, percent during the whole test p Example 11.Strept0kinase: dissolved 100,000 internal units of streptokinase were dissolved in 500 cc. of a 3.5% solution of the stabilizer defined in stabilizer Streptokinase Without stabilizer Example 12.-Strept0kinase: dry

300 mg. of the stabilizer defined in Exam added to 30 cc. of a streptokinase solution co cc. 250,000 of internal units. The solution t Streptokinase At 20 C., the solution remained stable for at least 6.5

distinction thereto, the stability did not chan ing the stabilizer of Example 1, of dilution Example 1. A corresponding control batch with a 0.85% Immediately after dissolution and after a standin 2 and 6.5 hours at 20 Streptplrinase with hours, which is about the time of a fusion. The difference to the activit used batch, which was already obser was within the accuracy of measure used for determining the activity.

without stabilizer were filled in a After dissolvin After freeze-(1r After 3 weeks at 37 C.

After 7 weeks at 37 C..

After 26 w7eks at 37 C The above data show that the stre bilized by the stabilizer when freeze-d stored for a period of more than a half a The preparation without stabilizer was after storage for 26 weeks at 37 C. only one third of its original activity where bilizer was found to have activity.

6 0 n nmo mm Cei 0 Wm nmoe .wu ur6 mvoS :1 8 USd ae e f .m nO b i a m v .m r eec e hfl a m efi 0 hc a Y .e a. m m n h 0 l e et m MM rm... av k m.dmm m m n m w mfi fl-l laa v n t tpa r umas o fl du wf m eu a hs vd e G a .b N w amntm w s m mmm m Tumau r f mwo Hf wow .1 m .w h0 M tm 0 av In contradistinction thereto, the hemagglutination of the undiluted New-Castle disease virus containing egg liquid fell after 5 weeks to half its original value and after 8 weeks a clear agglutination could no longer be determined. The egg liquid diluted in a ratio of 1:256 retained only for 2 weeks its full agglutination titer.

We claim:

1. A process for stabilizing biologically active material which comprises adding thereto 0.5 to 5.0 percent of modified collagen hydrolyzate containing cross-linking urea-alkylene-urea groups and having a molecular weight in the range of about 15,000 to 60,000.

2. A process as in claim 1 wherein said modified collagen hydrolyzate is a modified gelatin hydrolyzate.

- 3. A process as in claim 1 wherein 0.5 to 5.0 percent of sodium-L-glutamate is also added to said biologically active material,

4. A biologically active material stabilized with 0.5 to 5.0 percent of modified collagen hydrolyzate containing cross-linking urea-alkylene-urea groups and having a molecular weight in the range of about 15,000 to 60,000.

5. A stabilized material as in claim 4 wherein said modified collagen hydrolyzate is a modified gelatin hydrolyzate.

6. A stabilized material as in claim 4 which additionally contains 0.5-5.0 percent of sodium-L-glutamate.

References Cited UNITED STATES PATENTS 2,166,074 7/1939 Reichel 167-78 3,057,782 10/1962 Lindner et al. 16778 LEWIS GOTIS, Primary Examiner.

RICHARD HUFF, Assistant Examiner. 

4. A BIOLOGICALY ACTIVE MATERIAL STABLIZED ITH 0.5 TO 5.0 PERCENT OF MODIFIED COLLAGEN HYDROLYZATE CONTAINING CROSS-LNKING UREA-ALKYLENE-UREA GROUPS AND HAVING A MOLECULAR WEIGHT IN THE RANGE OF ABOUT 15,000 TO 60,000. 